Last Saturday, Sydney Water collected six water samples from different parts of the harbour beach front (sites 1-6 on the aerial image of the harbour) and one sample from a North Beach site.

The samples were analysed for ammonia, faecal coliforms and enterococci.

Sydney Water released the results of the testing on Wednesday afternoon.

A contractor has been working on the problem by site 1. Pictures: KIRK GILMOUR

It said high levels of ammonia were recorded at site 1 (the source of the sewage leak) and were negligible at the other six sites.

High levels of ammonia are indicative of the presence of raw sewage.

Very high levels of faecal coliforms - 4,400,000cfu per 100 millilitres - were also recorded at site 1.

The term "cfu" refers to "colony forming units" and is a measure of the number of different types of bacteria in the water samples.

The recommended levels for faecal coliforms in a "primary contact waterway" are less than 150cfu/100ml.

Acceptable levels were found at the other six sites.

Sydney Water said these results indicated the sewage has been diluted from the source at site 1.

The level of enterococci (a measurement used to assess swimming water quality in the NSW Beachwatch program) recorded at site 1 was 40cfu/100ml, which is above the primary contact swimming threshold of 35cfu/100 ml.

Levels at the other sites were below the acceptable limit.

Sydney Water said a private wastewater pipe servicing the Fishermen's Co-op building has been identified as the source of the leak.